The present invention relates to a device for signaling heating in a mechanical system, for example an anti-friction rolling bearing, main bearing or ball joint. The invention also relates to a mechanical system equipped with such a device. The invention relates to the field of security devices, in particular in the aeronautic maintenance field.
Mechanical systems of the rolling bearing, main bearing or ball joint type are commonly incorporated into all types of automobile, railroad, aeronautic or industrial machine equipment. For example, the mechanical system can be a ball bearing incorporated into an aeronautical device, such as a helicopter rotor.
In a known manner, such a mechanical system can undergo heating during operation. Beyond a critical temperature, certain component elements of the system can be irreparably damaged. The operation of the equipment into which the system is incorporated is then hindered, or even abruptly stopped. In certain cases, such a malfunction can therefore cause a serious accident.
In order to prevent or slow the heating of mechanical systems, a number of lubrication devices are known. Furthermore, the mechanical system can be provided with signaling devices, such as temperature sensors, making it possible to anticipate or signal critical heating.
International Publication WO/2008/107579 describes a mechanical system equipped with an autonomous device for injecting a fluid, in particular a lubrication or cooling fluid, into the system in case of heating. The device comprises a thermally triggered pyrotechnic charge generating combustion gas arranged in a housing. The fluid is contained in a reservoir separated from the charge by a moving piston on the one hand, and from the system by a membrane on the other hand. By reaching a predetermined ignition temperature, the charge undergoes combustion and the generated gases pressurize the fluid in the reservoir. The membrane breaks under the pressure from the fluid, which is then injected into the mechanical system. However, the triggering of the charge is not easily detectable from outside the device or system, for example by a maintenance operator, without using expensive electronic means.
The aim of the present invention is to propose a device for signaling critical heating that has been reached or is about to be reached, by a mechanical system. In particular, the invention targets a device that performs well and is reliable under demanding operating conditions, while being inexpensive and easy to implement.